1. Field of the Invention
This invention relates to a cassette loading apparatus suitable for use with a video tape recorder and the like, and more particularly to a cassette loading apparatus of the type wherein a cassette insertion detecting switch is operated into an on-state by a cassette inserted into a cassette holder.
2. Description of the Prior Art
A cassette loading apparatus for use with a video tape recorder of the front loading type is conventionally known and disclosed, for example, in Japanese Patent Laid-Open Application No. 60-111360, as including a cassette holder for moving a cassette between a cassette receiving position at which a cassette is inserted into or removed from the cassette holder and a cassette playing position at which recording or reproduction of video signals on a tape in a cassette is performed, and a cassette insertion detecting switch for detecting insertion of a cassette into the cassette holder to cause the cassette holder to start its movement from the cassette receiving position to the cassette playing position.
An exemplary conventional cassette loading apparatus is shown in FIGS. 5 and 6 to include a cassette holder 2 for receiving a cassette 1 therein, a cassette insertion detecting switch 3 in the form of a photocoupler or the like mounted on one of a pair of side walls 2a of the cassette holder 2, and a switch operating member 4 mounted on a bottom wall 2b of the cassette holder 2 for operating the cassette detecting switch 3 between on- and off-states. The cassette insertion detecting switch 3 is electrically connected by way of a flexible harness 5 to a cassette insertion detecting circuit (not shown) mounted on a stationary section of the video tape recorder.
When a cassette 1 is inserted in the direction indicated by an arrow a in FIG. 5 into the cassette holder 2 at its cassette receiving position as indicated by a solid line in FIG. 5, the switch operating member 4 is pushed to move in the direction of the arrow a by the cassette 1 against a return spring 6, whereupon the cassette insertion detecting switch 3 is operated from an off-state into an on-state by the cassette 1.
Consequently, a motor (not shown) of a cassette holder actuating apparatus (not shown) is rendered operative so that the cassette holder 2 is first drawn horizontally in the direction indicated by an arrow b from the cassette receiving position shown in FIG. 5 and then moved down vertically in the direction indicated by an arrow c to a cassette playing position shown in FIG. 6 for the recording/reproduction of video signals on a tape in the cassette 1 under the guidance of a plurality of guide rollers 7 mounted on the side walls 2a of the cassette holder 2 and a plurality of L-shaped guideways 9 formed in a pair of guide plates 8 mounted vertically on the chassis (not shown) and cooperating individually with the guide rollers 7. By such movement of the cassette holder 2, the cassette 1 is first drawn in the direction of the arrow b and then moved down vertically in the direction of the arrow c so that it is automatically loaded to its cassette playing position.
However, if a situation occurs that, after the cassette holder 2 starts its movement in the direction of the arrow b, the cassette 1 is, for example, inadvertently held by hand to cause the cassette holder 2 to leave the cassette 1 at the cassette receiving position, then the switch operating member 4 is returned in the direction indicated by an arrow a' by the spring 6 to cause the cassette insertion detecting switch 3 to be switched back into an off-state. Consequently, the motor is now driven reversely so that the cassette holder 2 is immediately returned in the direction indicated by an arrow b' to the cassette receiving position.
Such conventional cassette loading apparatus, however, is disadvantageous in that, since the harness 5 undergoes stress by expansion and flexure each time the cassette holder 2 is moved between the cassette receiving position and the cassette playing position, the harness 5 is short lived and relatively lacking in reliability.